1. Field of the Invention
The present invention relates to electromagnetic-coupling-module-attached articles, and more specifically, to an electromagnetic-coupling-module-attached article including a radio IC chip used in an RFID (Radio Frequency Identification) system.
2. Description of the Related Art
Recently, RFID systems, in which a reader/writer that generates an induction field and an IC tag (hereinafter, referred to as a radio IC device) storing predetermined information attached to an article communicate with each other in a non-contact manner to transmit information, have been developed as article management systems. Known radio IC devices used in the RFID systems, for example, are described in Japanese Unexamined Patent Application Publication No. 2005-136528 (Patent Document 1) and Japanese Unexamined Patent Application Publication No. 2005-244778 (Patent Document 2).
More specifically, as shown in FIG. 60, a radio IC device, in which an antenna element 601 is disposed on a plastic film 600 and a radio IC chip 610 is attached to one end of the antenna element 601, is provided. As shown in FIG. 61, a radio IC device, in which an antenna element 621 and radiation electrodes 622 are disposed on a plastic film 620 and a radio IC chip 610 is attached at a predetermined position of the antenna element 621, is provided.
However, in conventional radio IC devices, the radio IC chip 610 is DC-connected to and mounted on the antenna element 601 or 621 using Au bumps. Accordingly, positioning of the minute radio IC chip 610 on the large film 600 or 620 is required. Nevertheless, accurately positioning the minute radio IC chip 610 on the large film 600 or 620 is extremely difficult. The conventional radio IC devices have a problem that a resonant frequency characteristic at an antenna changes if the positioning thereof shifts during mounting. In addition, the resonant frequency characteristic at the antenna changes if the antenna element 601 or 621 is rolled or sandwiched between dielectrics (e.g., inserted inside a book).
Although applications for radio IC devices are virtually limitless, attaching the radio IC devices to various articles is difficult since the resonant frequency characteristic changes due to an arrangement state of antennas or other factors.